<template>
  <div class="spec-preview">
    <img ref="img1" :src="skuInfo.skuDefaultImg" />
    <div class="event" @mousemove="move"></div>
    <div class="big">
      <img ref="img2" :src="skuInfo.skuDefaultImg" :style="{left: -2 * left + 'px', top: -2 * top + 'px'}" />
    </div>
    <div class="mask" :style="{ left: left + 'px', top: top + 'px' }"></div>
  </div>
</template>

<script>
import { mapGetters } from 'vuex';
import _ from 'lodash';
export default {
  name: 'Zoom',
  data() {
    return {
      left: 0,
      top: 0
    };
  },
  computed: {
    ...mapGetters('detail', ['skuInfo'])
  },
  methods: {
    // move(e) {
    // debounce 防抖  throttle 节流
    move: _.throttle(function (e) {
      // console.log(e.offsetX,e.offsetY)
      // 100这个数值是mask这个盒子的宽度或是高度的一半 因为要让鼠标在mask的中心点
      // let x  = e.offsetX - mask.offsetWidth/2;
      let x = e.offsetX - 100;
      x = x < 0 ? 0 : x;
      x = x > 200 ? 200 : x;
      let y = e.offsetY - 100;
      y = y < 0 ? 0 : y;
      y = y > 200 ? 200 : y;
      // console.log(x, y);
      // console.log('move', this);
      this.left = x;
      this.top = y;
    }, 1000 / 60)
  },
  mounted() {
    this.$bus.$on('get-image', imgUrl => {
      // console.log(imgUrl);
      // this.$refs来获取页面中具有ref属性的标签对象
      // console.log(this.$refs,imgUrl);

      // 第1种方式
      // 以下写法直接操作DOM了,VUE框架 当中不推荐如此使用
      // this.$refs.img1.src = imgUrl
      // this.$refs.img2.src = imgUrl

      // 第2种方式 不直接操作DOM对象 只修改数据源
      this.skuInfo.skuDefaultImg = imgUrl;

      // 第3种方式
      //  this.skuInfo.skuDefaultImg = this.skuInfo.skuImageList[index].imgUrl
    });
  }
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>